Kassie, Abebaw (PhD)Misganaw, Tadiwos2018-07-022023-11-082018-07-022023-11-082016-06http://etd.aau.edu.et/handle/123456789/5269Internal audit has an important role in helping a firm to achieve its objective when it is implemented, operated, and managed effectively. Organizations which effectively implemented, operated and managed internal auditing were better able to identify their business risks and system inefficiencies for the sake of taking corrective actions and improvement in the process. The overall objective of the study is to identify the factors determining the effectiveness of internal audit in Ethiopian commercial banks. The study used purposive sampling method and covered the head office internal auditors of Ethiopian Commercial Banks. The study adopted mixed research method by employing quantitative and qualitative research methods. The quantitative research method used through 147 usable self administered questionnaires. These questionnaires were constructed in 5-point likert scale, distributed to internal auditors of Ethiopian Commercial Banks, and analyzed using SPSS statistical software. The qualitative research method used through personal interview with internal audit dir ectors of Ethiopian commercial banks and selected documents review. According to the results of the study; independence of internal audit, competence of internal audit team, and management supports were strong and statistically significant effect on the effectiveness of internal audit regarding on value adding role, enhance department performance, and enha nce organizational performance. In this regard, independence of internal audit, competence of internal audit teams and management supports were the factors determining effectiveness of internal audit in Ethiopian commercial banks. The researcher mainly recommended; give attention on the development of certified personnel, top management and IA team work collaboratively in changing audit culture, and to work in using IA softwares. Key words: Internal Audit, Ethiopian Commercial Banks, and Effectiveness of Internal Auditen-USInternal uditEthiopian commercial banksEffectiveness of Internal auditThesis